The chemical synthesis of insulin analogs is proposed. A fully- blocked A-chain with an intact 6-11 disulfide bridge will be constructed; combination of the A-chain with a suitably-blocked B-chain will be attempted. Various synthetic A-chains will be synthesized and the combination of these analogs with B-chain of natural sequence will also be evaluated. The A-B combination studies will involve the stepwise formation of the A20-B19 and A7-B9 cystine residues.